1. Field of the Invention
The present invention relates to an image forming apparatus and method, and a transferring medium cassette used in the image forming apparatus. The image forming apparatus and method utilize an indirect transferring method, in which a record-image is once formed on an intermediate transferring medium, then a layer including the formed record-image is transferred from the intermediate transferring medium to a target object, which requires image formation, such as a card-, sheet-, booklet-, or disk-like object (though the shape is not necessarily limited).
2. Description of the Related Art
An indirect transferring method is known, in which a mirror image of a record-image is formed on the image-forming layer of an intermediate transferring medium, and then the record-image is transferred onto a target object to form a normal image of the record-image. In this method, for example, the used intermediate transferring medium is formed of an intermediate transfer film having a film-like long substrate and the image-forming layer, which is disposed on the substrate and capable of being transferred onto the target object by separation from the substrate. For example, this method is utilized along with an image forming technique for forming a gradated and especially multi-colored image by means of thermal fusion transfer, thermally adhesive film separation transfer or the like, using a dot-on-dot method (a method of stacking differently colored dots one on another at substantially the same position to obtain a predetermined color) and an area gradation method (a method of setting gradations based on the dot sizes in pixels), or by means of sublimation transfer using a density gradation method, which utilizes thermal sublimation of sublimation dyes.
Specifically, in the primary transfer, only the ink layer of an ink ribbon, or sublimation dyes for sublimation transfer are selectively transferred to an intermediate transfer film by a thermal head, so that a record-image is formed. Then, the intermediate transfer film with the record-image is put on a target object, and is supplied with heat and pressure by a heating and pressing mechanism to perform the secondary transfer. By doing so, the record-image is transferred along with the image-forming layer from the intermediate transfer film onto the target object. Then, the intermediate transfer film is separated from the target object, so that the transfer of the record-image onto the surface of the target object is completed.
With this method, it is possible to transfer a record-image onto various kinds of objects, such as paper materials (normal paper, fine quality paper, art paper, synthetic paper, processed paper, etc.), plastic goods, metal goods, glass materials, and ceramics. Accordingly, an image can be formed on various kinds of target objects, such as booklets, e.g., bankbooks and passports, and other items, of, e.g., sheet or card.
FIG. 1 is a schematic structural view showing an image forming apparatus using a conventional indirect transferring method, while putting emphasis on the path of an intermediate transfer film and an ink ribbon in use.
As shown in FIG. 1, an intermediate transfer film 3 and an ink ribbon 4 pass between a thermal head 1 and a platen roller 2, which work as an image forming mechanism. The ink ribbon 4 is selectively heated by the thermal head 1 while the intermediate transfer film 3 and the ink ribbon 4 are put one on the other on the platen roller 2, so that a mirror image of a record-image is formed on the image-forming layer 10 (see FIG. 9) of the intermediate transfer film 3.
The intermediate transfer film 3 further passes between a heating roller 5 and a pressure roller 6, which work as a heating and pressing mechanism, and is set in a state where it is put around a guide roller 7 and a separation roller 8. A target object 9 is set on the right side in FIG. 1, and is sent between the heating roller 5 and the pressure roller 6. The intermediate transfer film 3 and the target object 9 are supplied with heat and pressure between the heating roller 5 and the pressure roller 6, so that the image-forming layer 10 of the intermediate transfer film 3 is transferred along with the record-image onto the target object 9.
In such an image forming apparatus, especially when the intermediate transfer film 3 is set, there is a case where the intermediate transfer film 3 is set at an improper position in the width direction, thereby disturbing the path of the film.
FIG. 2 is a perspective view showing a setting method of the intermediate transfer film 3, using the method above. When the intermediate transfer film 3 is replaced, the distal end of the outermost surface of the intermediate transfer film 3 is first fixed to a take-up reel 11 by a fixing tape 15 or the like. Then, a pay-off reel 13 is put and set on a pay-off axis connector 14 provided in the apparatus. Then, the take-up reel 11 is put and set on a take-up axis connector 12 provided in the apparatus, thereby completing the setting.
In another setting method (not shown), the pay-off reel 13 is first put and set on the pay-off axis connector 14 provided in the apparatus. Then, the take-up reel 11 is put and set on the take-up axis connector 12. Then, the distal end of the outermost surface of the intermediate transfer film 3 is fixed to the take-up reel 11 by a fixing tape 15 or the like, thereby completing the setting.
In either case of the setting methods described above, since the path of the intermediate transfer film 3 is long and not linear, it is difficult to properly (accurately) set the orientation of the transfer film at the position fixed by the fixing tape 15, thereby likely causing variations therein. Consequently, as shown in FIG. 3A, the intermediate transfer film 3 shifts in the width direction relative to a target object 9, when they are near a position directly below the heating roller 5 for performing secondary transfer. As a result, an image-forming layer 10 to be transferred shifts or crinkles on the target object 9, thereby bringing about transfer errors, such as a transfer positional shift 16 shown in FIG. 3B, or a transfer crinkle 17 shown in FIG. 3C.
In the case of image formation performed by thermal transfer using the dot-on-dot method and an area gradation method, it is important to accurately position and set the intermediate transfer film 3 to have a proper orientation. If the set orientation of the intermediate transfer film 3 positionally shifts, it is difficult to accurately stack differently colored ink dots at a predetermined position, thereby bringing about a problem in that hardly any high quality image with predetermined color or gradation can be obtained.
Furthermore, when the setting method described with reference to FIG. 2 is performed, key parts of image formation, such as the thermal head 1 and the platen roller 2, which are disposed near the path of the ink ribbon 4 and the intermediate transfer film 3, are contaminated directly or indirectly with foreign substances 18 and 19 (see FIG. 1, though they are exaggerated), such as dust and grease, which have stuck to the operator""s hands, clothes, and so forth. As a result, an image transferred to a target object is caused by the foreign substances 18 and 19 to have image defects 20 and 21 in the finally transferred matter, as shown in FIGS. 3D and 3E.
In the apparatus shown in FIG. 1, the ink ribbon 4 is also set by a method as in the intermediate transfer film 3. Consequently, also when the ink ribbon 4 is set, key parts of image formation in the apparatus are stained with foreign substances from operator""s hands, clothes, and so forth, thereby bringing about image defects 20 and 21 in the finally transferred matter, as shown in FIGS. 3D and 3E.
An object of the present invention is to provide an image forming apparatus and method, and a transferring medium cassette used in the image forming apparatus, which reduce the possibility of staining key parts of the image forming apparatus with foreign substances, when setting a long film-like article, such as an intermediate transfer film or an ink ribbon, which is consumed during formation of a record-image.
Another object of the present invention is to provide an image forming apparatus and method, and a transferring medium cassette used in the image forming apparatus, which allow a long film-like article, such as an intermediate transfer film or an ink ribbon, which is consumed during formation of a record-image, to be accurately set without dependence on the operator""s skill.
According to a first aspect of the present invention, there is provided an image forming apparatus comprising:
a mechanism configured to supply and drive a long film-like ink ribbon having an ink layer for performing thermal transfer recording;
a mechanism configured to supply and drive a long film-like transferring medium having an image-forming layer, which allows thermal transfer recording to be performed, using the ink ribbon, and is separable from a substrate;
a platen configured to support the transferring medium when thermal transfer recording is performed on the image-forming layer, using the ink ribbon;
a thermal head configured to selectively heat the ink layer of the ink ribbon in a state where the transferring medium and the ink ribbon are put one on the other on the platen, thereby selectively transferring a thermal transfer recording material onto the image-forming layer to form a record-image on the image-forming layer; and
a heating and pressing mechanism configured to apply heat and pressure to the transferring medium having the record-image and a target object, in a state where the transferring medium and the target object are put one on the other, thereby transferring the record-image along with the image-forming layer from the transferring medium to the target object;
wherein at least one long film-like article to be consumed when the record-image is formed on the image-forming layer is accommodated in a cassette detachably mounted in the apparatus, and the long film-like article is used for forming the record-image while being fed from the cassette mounted in the apparatus.
In a second aspect of the present invention, there is provided an apparatus according to the first aspect, wherein the cassette includes a casing, a pay-off shaft rotatably disposed on the casing to support the long film-like article in a virgin state put therearound, and a take-up shaft rotatably disposed on the casing to wind up the long film-like article in a spent state.
In a third aspect of the present invention, there is provided an apparatus according to the second aspect, wherein the cassette includes openings respectively formed on two opposite surfaces of the casing between the pay-off shaft and the take-up shaft, such that an operation head of the apparatus for the long film-like article comes into the casing through one of the openings and pushes the long film-like article out of the casing through the other of the openings, when the long film-like article is used for forming the record-image.
In a fourth aspect of the present invention, there is provided an apparatus according to the second or third aspect, wherein the pay-off shaft and the take-up shaft are detachably disposed on the casing to allow the cassette to be refilled with a long film-like article.
In a fifth aspect of the present invention, there is provided an apparatus according to any one of the second to fourth aspects, wherein the apparatus comprises first and second axis connectors configured to respectively attach the pay-off shaft and the take-up shaft thereto, the second axis connector functioning as a driving shaft to drive the long film-like article.
In a sixth aspect of the present invention, there is provided an apparatus according to any one of the first to fifth aspects, wherein the transferring medium is accommodated in a first cassette, corresponding to an arrangement of the long film-like article accommodated in the cassette.
In a seventh aspect of the present invention, there is provided an apparatus according to the sixth aspect, wherein the platen is movable between a first operation position and a first retreat position, which are located to sandwich a mounting position of the first cassette, such that the platen is placed at the first retreat position before the first cassette is mounted in the apparatus, and the platen is placed at the first operation position while pushing the transferring medium out of the first cassette through an opening in the first cassette after the first cassette is mounted in the apparatus.
In an eighth aspect of the present invention, there is provided an apparatus according to the seventh aspect, wherein a heating and pressing mechanism is supported by a rotatable block common to the platen, and the apparatus comprises an operation head movable in response to movement of the platen while the platen is moved between the first operation position and the first retreat position.
In a ninth aspect of the present invention, there is provided an apparatus according to any one of the first to eighth aspects, wherein the ink ribbon is accommodated in a second cassette, corresponding to an arrangement of the long film-like article accommodated in the cassette.
In a tenth aspect of the present invention, there is provided an apparatus according to the ninth aspect, wherein the thermal head is movable between a second operation position and a second retreat position, which are located to sandwich a mounting position of the second cassette, such that the thermal head is placed at the second retreat position before the second cassette is mounted in the apparatus, and the thermal head is placed at the second operation position while pushing the ink ribbon out of the second cassette through an opening in the second cassette after the second cassette is mounted in the apparatus.
In an eleventh aspect of the present invention, there is provided an apparatus according to any one of the first to fifth aspects, wherein the transferring medium and the ink ribbon are accommodated in a common cassette, each corresponding to an arrangement of the long film-like article accommodated in the cassette.
In a twelfth aspect of the present invention, there is provided a cassette formed as the first cassette according to the sixth aspect, which accommodates a long film-like transferring medium having an image-forming layer, which allows thermal transfer recording to be performed, using an ink ribbon having an ink layer, and is separable from a substrate, wherein the transferring medium is used for forming a record-image while being fed from the cassette mounted in an image forming apparatus.
In a thirteenth aspect of the present invention, there is provided a cassette according to the twelfth aspect, wherein the cassette includes a casing, a pay-off shaft rotatably disposed on the casing to support the transferring medium in a virgin state put therearound, and a take-up shaft rotatably disposed on the casing to wind up the transferring medium in a spent state.
In a fourteenth aspect of the present invention, there is provided a cassette according to the thirteenth aspect, wherein the cassette includes openings respectively formed on two opposite surfaces of the casing between the pay-off shaft and the take-up shaft, such that an operation head of the apparatus for the transferring medium comes into the casing through one of the openings and pushes the transferring medium out of the casing through the other of the openings, when the transferring medium is used for forming the record-image.
In a fifteenth aspect of the present invention, there is provided a cassette according to the thirteenth or fourteenth aspect, wherein the pay-off shaft and the take-up shaft are detachably disposed on the casing to allow the cassette to be refilled with a transferring medium.
According to a sixteenth aspect of the present invention, there is provided an image formation method comprising:
supplying and driving a long film-like ink ribbon having an ink layer for performing thermal transfer recording;
supplying and driving a long film-like transferring medium having an image-forming layer, which allows thermal transfer recording to be performed, using the ink ribbon, and is separable from a substrate;
selectively heating the ink layer of the ink ribbon by a thermal head in a state where the transferring medium and the ink ribbon are put one on the other on a platen, thereby selectively transferring a thermal transfer recording material onto the image-forming layer to form a record-image on the image-forming layer; and
applying heat and pressure to the transferring medium having the record-image and a target object, in a state where the transferring medium and the target object are put one on the other, thereby transferring the record-image along with the image-forming layer from the transferring medium to the target object;
wherein at least one long film-like article to be consumed when the record-image is formed on the image-forming layer is accommodated in a cassette detachably mounted in an image forming apparatus, and the long film-like article is used for forming the record-image while being fed from the cassette mounted in the apparatus.
In a seventeenth aspect of the present invention, there is provided a method according to the sixteenth aspect, wherein the transferring medium is accommodated in a first cassette, corresponding to an arrangement of the long film-like article accommodated in the cassette.
In an eighteenth aspect of the present invention, there is provided a method according to the seventeenth aspect, wherein the platen is movable between a first operation position and a first retreat position, which are located to sandwich a mounting position of the first cassette, the method comprising:
placing the platen at the first retreat position before the first cassette is mounted in the apparatus; and
placing the platen at the first operation position while pushing the transferring medium out of the first cassette through an opening in the first cassette after the first cassette is mounted in the apparatus.
In a nineteenth aspect of the present invention, there is provided a method according to any one of the sixteenth to eighteenth aspects, wherein the ink ribbon is accommodated in a second cassette, corresponding to an arrangement of the long film-like article accommodated in the cassette.
In a twentieth aspect of the present invention, there is provided a method according to the nineteenth aspect, wherein the thermal head is movable between a second operation position and a second retreat position, which are located to sandwich a mounting position of the second cassette, the method comprising:
placing the thermal head at the second retreat position before the second cassette is mounted in the apparatus; and
placing the thermal head at the second operation position while pushing the ink ribbon out of the second cassette through an opening in the second cassette after the second cassette is mounted in the apparatus.
The embodiments of the present invention include inventions at various stages, and various types of inventions can be derived from appropriate combinations of a plurality of disclosed constituent elements. For example, when an invention is derived by omitting several constituent elements shown in the embodiments, to practice the derived invention, the omitted portions are compensated for by known conventional techniques.
According to the present invention, an intermediate transfer film used as a transferring medium is accommodated in a cassette, and is set at a predetermined position in an image forming apparatus. Accordingly, near a position directly below a heating roller for performing secondary transfer, the set direction of the film relative to a predetermined position in the film width direction is prevented from carelessly shifting. As a result, it is possible to prevent such faulty-transfer relative to a target object, that an image-forming layer causes transfer positional shifts in the film width direction or transfer crinkles.
Furthermore, not only the intermediate transfer film, but also an ink ribbon used for writing a record-image preferably employs a cassette structure, thereby further suppressing contamination near the set path. As a result, it is possible to prevent image defects from being caused by foreign substances on the finally transferred matter.
In other words, even where the path of the intermediate transfer film is long and complicated, a uniform and high-quality record-image with no image defect is completed without dependence on the skill of the operator who performs setting of the intermediate transfer film and the ink ribbon.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.